There is a long-felt need for steering mechanisms that may be conveniently arranged in and integrated with toy vehicles and other small devices. A steering mechanism controls, for example, the direction of travel of the front wheels of a toy sports car. The steering mechanism may be remotely controlled so that the car can be remotely steered.
Applicant has developed a novel steering mechanism for turning the front (and/or rear) wheels of a toy vehicle. The steering mechanism may be remotely controlled using a motorized gear box that controls the steering position of the mechanism. The gear box includes a motor that may be activated remotely, such as via a wireless transmission link. The motor in the gear box turns gears in the gear box that turn a steering arm of the steering mechanism. The steering arm engages and turns a steering carriage to turn the wheels of the vehicle.
The steering mechanism may include a steering arm that is coupled to the front wheels via a steering carriage. The front wheels of the vehicle are connected to the steering carriage. The carriage align the front wheels such that they both are pointed in the same direction. The carriage causes the wheels to turn in unison as the carriage is pivoted by the steering arm. The steering arm is attached at one end to an output shaft of a gear box. The opposite end of the steering arm engages the steering carriage. As the gear box causes the steering arm to pivot about the end of the arm coupled to the gearbox output. As the gear box pivots the steering arm through a range of approximately 30.degree. or 40.degree. to the left and to the right from top-dead center, the steering arm pivots the carriage and causes the wheels to turn.
The steering mechanism has a center position. When in this center position, the carriage and wheels are aligned for straight ahead travel (or, alternatively, the wheels may be aligned for a wide left or right turn). A return spring in the steering mechanism biases the steering arm to its center position. The spring causes the steering arm to be in its center position when the motor in the gear box is not activated to turn the wheels. The motor overcomes the spring force to turn the steering arm, carriage and wheels, but the spring force returns the arm to center the wheels of the vehicle when the motor is de-energized. The steering mechanism may also include a steering trim device that enables a toy operate to adjust the center position of the steering mechanism.
The inventive steering mechanism has a simplified and easy-to-form structure. The steering arm includes an annular collar that is directly coupled to the output of the gear box.
In addition, the trim adjustment is a simple cylindrical arrangement having an axially-offset post that adjusts the center position of the steering arm return springs and hence the steering arm. The trim cylinder has a manual set tab that allows an operator to adjust the center position of the steering mechanism and hence the wheel alignment.
An advantage of the steering mechanism is that it is compact and fits nicely around a gear box. The steering mechanism and gear box can be easily fit into the under-carriage of a toy vehicle. Another advantage is that the steering mechanism is formed of three plastic parts and a simple coiled spring which reduces construction costs and simplifies assembly of the steering mechanism. The primarily plastic steering mechanism is safe, especially in view of conventional steering mechanisms that tend to be formed of several metal parts that can injure children. Another safety feature is that the plastic parts that constitute the steering mechanism are attached by a screw to the gear box such that the components of the mechanism are not easily detached from the toy. In addition, the steering mechanism and gear box can be completely contained within the undercarriage of the vehicle so that children cannot easily reach the steering mechanism. The alignment set tap is the only portion of the steering mechanism that is visible and reachable by children.
The gear box drives the steering mechanism. The gear box transmits rotation and torque through an assembly of intermeshing rotating gears. An input shaft to the gear box transmits a drive rotation to the gears and to an output shaft(s) from the box. As the drive rotation causes the intermeshing gears in the box to rotate, the rotational speed of each of the gears will vary depending on the gear teeth ratios of each pair of gears. The torque and rotational speed of the output shaft will be in proportion to the input shaft speed and torque, where the proportional relationship depends on the arrangement of gears between the input and output shafts.
The motorized gear box may include a housing that entirely encases the gears, so that dirt and dust cannot easily come between the gears. The gear boxes may also be integral with the housing of the toy to minimize the components in the toy and to reduce manufacturing costs. If an integral gear box is not practical, then an encasing gear box may be designed to fit easily in the housing of the toy adjacent to the wheels, mechanical arm or other component to be turned by the gear box. Accordingly, the gear boxes of the present invention seal the gears against dirt and dust, and may be integrated into the plastic housing of a toy or for a separate housing mounted within the toy.
The invention provides several advantages for steering mechanisms and gear boxes over the prior art including, but not limited to: improved safety, better resistance to dirt and grime, fewer components (especially metal components), lower manufacturing costs, and compact arrangements of motor and transmission gear assemblies. Safety is improved, especially for toys, because the invention reduces the number of small gears and other components needed for a steering transmission assembly and thereby reduces the number of components that may be separated from a toy and inadvertently swallowed by child. Safety is also improved by having spur gears formed of plastic, which is less likely to cut a child, than would metal spur gears. The invention resists dirt and grime by encapsulating gears and motors in gear boxes. The lower manufacturing costs flow from forming spur gears and steering mechanisms from plastic, rather than metal, and reducing the number of gears and other components previously used in gear boxes and steering mechanisms. In addition, compact arrangements of motors and transmission gear assemblies is achieved because the use of spur gears allows the motor to be arranged adjacent to the gear assembly.